自动登录

 自动登录，是将客户端登录验证通过的信息记录在客户端的cookie里，当下次登录时，通过cookie中记录的用户ID和Token，与数据库中的用户登录状态进行比较，比较通过以后自动登录。

1、验证通过以后，写入cookie

  HttpCookie identityCookie = new HttpCookie("identity");
            identityCookie.HttpOnly = false;
            identityCookie.Expires = DateTime.MaxValue;
            identityCookie["userID"] ="2";
            identityCookie["token"] = (new Guid("837A2825-5649-4686-A071-FC3C8D267123")).ToString();
            HttpContext.Request.Cookies.Add(identityCookie);
            HttpContext.Response.Cookies.Add(identityCookie);

2、判断是否已登录

   public bool IsLogin
        {
            get { return LoginUser != null; }
        }

        public User LoginUser
        {
            get
            {
               var user= HttpContext.Items["identity"] as User;
                if(user==null)
                {
                    //判断是否记录过cookie
                    var cookIdentity = HttpContext.Request.Cookies["identity"];
                    if (cookIdentity != null)
                    {
                        var userID =int.Parse(cookIdentity["userID"]);
                        var  token =new Guid(cookIdentity["token"]);
                        //var mac = cookIdentity["mac"];
                        LoginHelp loginHelp=new LoginHelp();
                       user= loginHelp.GetUserByToken(userID,token);
                        HttpContext.Items["identity"] = user;
                    }
                }
                return user;
            }
        }

3、判断是否已登录，已登录就进行跳转

  [HttpGet]
        public ActionResult Login()
        {
            if (Logined)
            {
                return RedirectToAction("Index");
            }
            return View();
        }

接下来要写两篇文章，对HttpContext和cookie进行了解。